Towards a Series of Design Rules for Homogeneous Catalysis: Synergy Between Experiment and Theory

Despite currently shrinking energy supplies and growing industrial environmental impact, demand continues to rise for products manufactured under forcing conditions (eg. high temperature, pressure), often in the presence of toxic solvents. Industry is continually searching for novel means to reducing production expense and environmental impact. The lack of transferability between existing solutions entails starting anew for each class of reactions. Rational design and optimisation of efficient catalysts presents a solution; it also represents one of the ultimate challenges in the molecular sciences, particularly for homogeneous systems. Catalysis has the highest industrial and environmental impact, opening up never-before-possible ways of creating new bonds and compounds besides imparting pollution reduction and energy efficiency to existing processes.A proposal is made to initiate a novel research line to establishing a central methodology towards characterising homogeneous cross-coupling catalysts, by experiment and theory, towards adding to a growing body of 'design rules' thereof. Focus involves the theoretical characterisation of 2 differing cross-coupling mechanisms. Subsequent wavefunction and electronic structure analyses will be carried-out jointly with collaborators. Both the desired product (cross-coupling) and main side-product (arising from beta-hydride elimination) formations will be studied, for selected Ni and Pd-containing systems. Catalyst samples as well as complexes and variations thereof will be synthesised and their reactivities characterised by project collaborators. Results will aid the candidates concurrent pioneering of theory-designed neutron spectroscopy (NS) experiments to quantify substituent alkyl-group dynamics and their coupling to catalyst flexibility, substrate coordination and electronic structure at the catalytic centre.An EPSRC award would be strategic in helping the candidate contribute to the rational optimisation and design of cross-coupling catalysts and to extend the application of NS. The project would be instrumental in establishing the candidate as a world authority in the theoretical and spectroscopic characterisation of existing homogeneous catalysts and design of novel catalysts.This is a demanding project with the objective of advancing the rational design of highly active cross-coupling catalysts, apriori using computation. Therefore, a fundamental understanding at the molecular level of the steric and electronic nature of the ligand and metal centre is essential. Since most organic reactions take place in solvent and not in a vacuum or a static dielectric field, it is pivotal (no matter how challenging!), to develop an accurate method for including the effect of solvent. As the candidate has already co-authored several high-impact publications in this area, this project will focus on the realisation of catalysed reactions in the presence of a reliable explicit solvent model. The findings of the above program of research will be of vast interest to the wider physical, theoretical, synthetic and industrial communities, as witnessed by the recent publicity detailed from ISI Web of Science searches and the candidate's own co-corresponded work highlighted in the September 2009 issue of C&E News.

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